President Jacob Zuma of South Africa has urged the African National Congress to identify and punish party members who voted against him in a no-confidence motion in parliament on August 8.

Some 30 ANC lawmakers supported the opposition motion in a secret ballot, not enough for it to pass but the defection exposed rifts within the ANC that could weaken Zuma’s ability to influence the choice of next party leader at elections in December.

Addressing an ANC meeting, Zuma called the defectors “people who have double hearts, one for the ANC and one for other parties,” and said they “must be taken to the (ANC) disciplinary committee,” South African media reported.

“What our enemies (opposition members of parliament) were doing was to say: ‘How can we destroy the ANC and weaken it, so that we can take control of the country?’ … We should never do it again,” Zuma was quoted as saying.

It was unclear how the party would be able to determine who had voted against Zuma or what action could be taken against them.

The president said he would discuss the issue of dissenters at a meeting of the ANC on Monday.

ANC communications officials were unavailable to comment.

Critics say Zuma’s priority is to ensure he retains sufficient control over the party to ensure that his chosen candidate succeeds him as leader so he can avoid scrutiny over corruption allegations that have dogged his eight years in power.

Zuma has denied wrongdoing.

The opposition sought to oust Zuma after he removed finance minister Pravin Gordhan in March, a move that hit the financial markets and prompted two credit ratings agencies to downgrade South Africa’s debt rating to junk status.

Following the failure of the no-confidence motion, the main opposition Democratic Alliance party said it would bring a motion to dissolve parliament and call a general election.

The ANC, which has a strong majority in the assembly, dismissed the DA’s call as “dreams and hallucinations.”